Bill at php explained what that was for and I forgot what he said and why.
So it's not used. I wouldn't worry about it.

The PLUG is for when you bring your truck to the DEALER!
If you go to the dealer for service work to your truck it's always a good idea to put back to stock and to take the gryphon out. Not unless there is an agreement made that they won't reflash your PCM without approval. Once they reflash your HEX code changes and that code is the building block for your custom tunes.

Lars

Thanks! That was good info..

Thanks everyone that clears it up!

Welcome to the forum!

Ty